ABSTRACT
A
Single Phase Dynamic Voltage Restorer (DVR) based on five-level ground point
shifting multilevel inverter topology has been proposed in this paper. The
proposed inverter has a floating ground point. Therefore, by shifting the
ground point, it is observed that the inverter circuit gives five output voltage
levels from single DC voltage source. This configuration uses less number of
switches compared to the existing multilevel inverter topologies. A fast sag
swell identification technique using d-q reference frame is also discussed in
this paper. This proposed topology of the DVR can compensate voltage sag,
swell, flicker and maintain the required voltage at the load bus. The detailed simulation
study is carried out using MATLAB/Simulink to validate the result.
KEYWORDS
1. Voltage
sag
2. Swell
3. Ground
Point Shifting Multilevel Inverter (GPSMI)
4. Topology
5. DVR
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM
Fig.
1. General structure of the proposed DVR.
Fig.
2. (a) Grid terminal voltage (vt) and (b) load voltage (vl) during sag
mitigation.
Fig.
3. direct axis value of the d-q reference frame which is used to detect
Fig.
4. During voltage sag (a) grid terminal voltage (vt), (b) series injected
voltage
(vinj) and (c) inverter terminal voltage (vinv).
Fig.
5. FFT analysis of the series injected voltage (vinj).
Fig.
6. (a) Grid terminal voltage and (b) load voltage during Voltage flicker
CONCLUSION
This
paper proposes dynamic voltage restorer based on the ground point shifting
multilevel Inverter topology (GPSMI). The operation of the multilevel inverter
and the power circuit diagram is explained. The inverter topology requires less
number of switches than conventional multi-level inverter. In this inverter
topology, only two switches are active at any instant of time that reduce
switch conduction loss. The passive filter requirement in the DVR topology is
reduced by using this multi-level inverter. Proper PWM for this proposed inverter
has been explained. Instantaneous sag identification technique using d-q
reference frame has also been explained. This proposed DVR can mitigate the
power quality problem like sag/swell and voltage flicker.
REFERENCES
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[3]
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[4]
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